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LPC1549 I2C master never pending after transfer start

Question asked by Donald Rosendahl on Oct 5, 2018
Latest reply on Oct 16, 2018 by Kerry Zhou

I am trying to get I2C master working on an LPC1549JBD100. When executing Chip_I2CM_XferBlocking the process hangs on (!Chip_I2CM_IsMasterPending(pI2C)). The code is based on the periph_i2cm_polling example from LPCopen v2.20.

 

I have verified that I can control the pins when configured as PIO0_22 and PIO0_23. When configured as SDA and SCL I see some clock signals during/after initialization, but never when the actual data should be transmit.

 

The SDA and SCL lines are connected to a logic analyzer, both when testing on the LPCXpresso1549 and on the custom hardware. Differences are that the evaluation board uses the LPC1549JBD64 while the custom hardware uses an LPC1549JBD100. Another difference is that the custom hardware uses external pull-ups to 5V while the evaluation board uses external pull-ups to 3.3V.

 

What could be the cause of the I2C master never transmitting and returning to pending state? If more information is required, please let me know and I will post it as soon as possible.

 

Best regards,

Donald Rosendahl

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